Monthly Archives: October 2007

More Prius

I thought I’d provide a little more about the Toyota Prius that Trish and I bought last week, now that I’ve driven it around a lot and have more to say.

First of all, it’s a 2008 Prius with “Package B”. The base Prius has power windows & locks, air conditioning, and the other “usual” stuff for a car in its price range. The Package B includes heated mirrors, a rear-view camera for reversing, cruise control, and the smart key system.

The smart key system is one of my favorite features unrelated to the fact that it’s a hybrid. The smart key is so nice because I never have to take it out of my pocket. If the key is within 3 feet of the door handle and I touch the door handle, the car will unlock so I can open the door. Same with the trunk. Then I just sit down in the car, and it senses that the key (still in my pocket) is inside of the car, and thus allows me to start the car.

Starting the car is another story. I simply depress the brake pedal and press the large circular “Power” button on the dash. The dash lights up, the car beeps, and the “Ready” indicator comes on, and the car is ready to roll. Usually the engine comes on a few seconds after this, in order to charge up the battery a bit. But I can move the shift lever to “D” or “R” and start moving immediately, before the engine comes on. If I put it in “R”, the touch-screen LCD in the center of the dash (which by default displays energy flow and consumption information) switches to the rear-view camera.

The touch-screen LCD in the dash is also used for climate control (heater, air conditioning, etc.) and can be used for audio control as well — browsing files on an MP3 CD, for example. The default view, Energy Flow, shows an overhead cartoonish cutout of the car with the engine, electric motor, wheels, and battery all with arrows between them that change and show the flow of energy while the car is driving. You can also tap the “Consumption” button on the screen to show a graph of fuel mileage every 5 minutes since the car was turned on.

What’s really freaky is when you are pulling up to a stop sign and the engine dies. It is difficult to suppress one’s instinct to think “my car died!” and become worried. However it is perfectly normal for the Prius to turn off the engine when slowing down and at other random times when energy can be saved by not running the gas engine. Yesterday I was driving 45 mph, and I slowed to 40 mph to feel safer in a particular half-mile stretch of the road. The gas engine turned off and I drove the entire half mile at 40 mph on electric-only. It felt so cool!

The gas engine also is typically off when I’m driving around in a parking lot or in stop-and-go traffic, at low speeds. It’s not efficient for the gas engine to be running at those low speeds, so it doesn’t. It waits until the car is going fast enough to make good use of the gas, then turns on the engine to drive the car (and recharge the battery, if it still has excess energy production).

Trish and I drove down to the south end of Whidbey Island on Friday night and back on Saturday night, and we averaged over 50 miles per gallon for the trip. Some sections were over 75 mpg (like when driving through Oak Harbor during rush hour almost entirely off the battery). Weeeee!

Here’s a summary of the ways I can think of that causes the Prius to have better gas mileage that other modern cars in its class:

  • Braking generates electricity to recharge the batteries, storing energy. Most other cars turn this energy in to heat at the brakes, which is just wasted energy.
  • Coasting generates electricity to recharge the batteries, storing energy. Other cars just run their engine uselessly while coasting. Note that sometimes the engine is on when coasting, in which case all of the energy it generates is stored in the batteries. If the engine is off, some energy is still being stored up by the generators (it’s like braking very lightly).
  • Driving down hill is the same thing as coasting, storing energy. Most other cars still burn up energy and throw it away when going down-hill.
  • When the gasoline engine is running, it almost always runs at its most efficient speed. If this speed is too fast, the excess energy is stored up in the batteries. If this speed is too slow, energy is pulled from the batteries.
  • Stemming from the previous item, when quick acceleration is required, previously stored energy is pulled from the batteries to supplement the underpowered (but efficient!) gasoline engine.

In summary, the Prius stores up energy that is typically wasted in other cars and is then able to utilize that energy at a later time, instead of throwing away energy. This makes it a very efficient car.

That’s all for now. 🙂

Toyota Prius

Trish and I bought a Toyota Prius this afternoon. We traded in both of our cars, and ended up getting lower payments on this one than on my old MINI. Yay!

It’s a cool car, too. Very fancy and neato and stuff. Yay!